Sound Problems with JVC AV-35BP4 TV. The internal speakers on my JVC AV-35BP4 TV are not working,

Question

The internal speakers on my JVC AV-35BP4 TV are not working, nor can I get TV sound out of the external speakers I have hooked up through my receiver. I know the reveiver/speakers work because other applications run through the receiver work fine.

There is an EXT SPKR switch on the back of the TV and I've tried it in all positions...still no sound.

Any ideas?I have aPS32700yx1 proscan tv.The sound works when we play videos and dvd's but when we watch tv there's no sound.